Electric drive system and transportation tools

Abstract

The present disclosure proposes an electric drive system and a means of transportation, and relates to the technical field of safety state control of electric drive systems. The system includes: a three-phase inverter unit, a motor, a speed detection unit, and a gate driver; the speed detection unit is connected to the motor and the gate driver respectively, and the speed detection unit is used to determine whether the speed state of the motor is a high-speed state or a low-speed state, and transmit the speed state to the gate driver; the gate driver is connected to the motor through a three-phase inverter unit, and the gate driver is used to control the opening or closing of the power switch tube in the three-phase inverter unit based on the speed state, so as to adjust the safety state of the electric drive system to an active short circuit state or a winding open circuit state, by adding a speed detection unit to detect the speed of the motor, determining the speed state of the motor, and controlling the opening or closing of the power switch tube in the three-phase inverter unit through the gate driver, the safety state control of active short circuit or winding open circuit in the electric drive system is realized, and the overall safety is improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of safety state control of electric drive systems, and in particular to an electric drive system and a means of transportation. Background Art

[0002] With the trend of electrification and intelligence in the automotive industry, the safety requirements of automobiles are increasing. In order to ensure the safety of automotive electronic control systems, international mainstream car manufacturers have put forward higher safety requirements for automotive electric drive systems, especially to prevent unexpected acceleration or deceleration. Among them, the two commonly used safety states of motors in electric drive systems are active short circuit (ASC) and open winding (FreeWheel). When the vehicle speed is low, the electric drive system will choose to enter the open winding state to prevent the permanent magnet synchronous motor from generating unexpected braking torque. When the vehicle speed is high, the motor in the electric drive system will choose to enter the active short circuit state to avoid the high passive rectification current generated by high back electromotive force, thereby reducing unexpected braking torque.

[0003] At present, the electric drive system of the related technology is equipped with a rotor position sensor, and the single-chip microcomputer detects the motor speed by reading the signal of the position sensor, so as to determine the safety state of the electric drive system. However, when the single-chip microcomputer fails, the motor speed cannot be detected, and the vehicle speed at the time of the failure cannot be accurately determined, and it is impossible to switch to the corresponding safety state according to the vehicle speed, which affects the overall safety of the vehicle. Summary of the invention

[0004] The present disclosure provides an electric drive system and a means of transportation.

[0005] According to a first aspect of the present disclosure, an electric drive system is provided, the system comprising: a three-phase inverter unit, a motor, a speed detection unit and a gate driver; the speed detection unit is connected to the motor and the gate driver respectively, the speed detection unit is used to determine whether the speed state of the motor is a high-speed state or a low-speed state, and transmit the speed state to the gate driver; the gate driver is connected to the motor through the three-phase inverter unit, and the gate driver is used to control the opening or closing of the power switch tube in the three-phase inverter unit based on the speed state, so as to adjust the safety state of the electric drive system to an active short-circuit state or a winding open-circuit state.

[0006] In some embodiments, the speed detection unit includes: a back electromotive force shaping circuit, a pulse width signal conversion circuit, a low-pass filter circuit and a comparator circuit; the back electromotive force shaping circuit is respectively connected to the motor and the pulse width signal conversion circuit, and is used to obtain the back electromotive force signal of the motor, convert the back electromotive force signal into a square wave signal, and transmit the square wave signal to the pulse width signal conversion circuit; the pulse width signal conversion circuit is connected to the low-pass filter circuit, and is used to convert the square wave signal into a fixed pulse width signal with the same frequency as the square wave signal, and transmit the fixed pulse width signal to the low-pass filter circuit; the low-pass filter circuit is connected to the comparator circuit, and is used to filter the fixed pulse width signal into a DC signal, and transmit the DC signal to the comparator circuit; the comparator circuit is connected to the gate driver, and is used to determine whether the DC voltage corresponding to the DC signal is greater than or equal to the threshold voltage, and according to the judgment result, determine the speed state of the motor, and send the speed state to the gate driver.

[0007] In some embodiments, the three-phase inverter unit includes: a first switch tube bridge arm, a second switch tube bridge arm and a third switch tube bridge arm; the first switch tube bridge arm is formed by connecting the first power switch tube and the second power switch tube in sequence; the second switch tube bridge arm is formed by connecting the third power switch tube and the fourth power switch tube in sequence; the third switch tube bridge arm is formed by connecting the fifth power switch tube and the sixth power switch tube in sequence.

[0008] In some embodiments, the motor includes: a first winding, a second winding, and a third winding.

[0009] In some embodiments, the midpoint of the first switch tube bridge arm is connected to the first winding to form a first phase drive circuit; the midpoint of the second switch tube bridge arm is connected to the second winding to form a second phase drive circuit; the midpoint of the third switch tube bridge arm is connected to the third winding to form a third phase drive circuit.

[0010] In some embodiments, the back electromotive force shaping circuit includes a first comparator, a first resistor, a second resistor and a third resistor; the first end of the first resistor is connected to the second phase driving circuit, and the second end of the third resistor is connected to the third phase driving circuit; the second end of the first resistor is connected to the non-inverting input end of the first comparator; the first end of the third resistor is connected to the inverting input end of the first comparator;

[0011] The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first end of the third resistor; the first power supply end of the first comparator is connected to the power supply, and the second power supply end is grounded; the output end of the first comparator is connected to the pulse width signal conversion circuit.

[0012] In some embodiments, the pulse width signal conversion circuit includes a monostable trigger, a first capacitor, and a fourth resistor; the rising edge trigger input terminal of the monostable trigger is connected to the output terminal of the first comparator; the falling edge trigger input terminal of the monostable trigger is grounded; the first external capacitor terminal of the monostable trigger is connected to the second terminal of the first capacitor; the first terminal of the first capacitor is connected to the second external capacitor terminal of the monostable trigger, the second external capacitor terminal is connected to the second terminal of the fourth resistor, and the first terminal of the fourth resistor is connected to the power supply; the power supply terminal of the monostable trigger is connected to the power supply, and the ground terminal is grounded; the output terminal of the monostable trigger is connected to the low-pass filter circuit.

[0013] In some embodiments, the low-pass filter circuit includes a fifth resistor, a sixth resistor, a second capacitor, and a third capacitor; the first end of the fifth resistor is connected to the output end of the monostable trigger; the second end of the fifth resistor is connected to the first end of the sixth resistor; the first end of the second capacitor is connected to the second end of the fifth resistor, and the second end of the second capacitor is grounded; the first end of the third capacitor is connected to the second end of the sixth resistor, and the second end of the third capacitor is connected to the second end of the second capacitor; the second end of the sixth resistor is connected to the comparator circuit.

[0014] In some embodiments, the comparator circuit includes a second comparator; the inverting input terminal of the second comparator is connected to the second end of the sixth resistor; the non-inverting input terminal of the second comparator is connected to the threshold voltage output terminal; and the output terminal of the second comparator is connected to the gate driver.

[0015] According to a second aspect of the present disclosure, a means of transport is provided, comprising the electric drive system according to the first aspect.

[0016] According to an embodiment of the present disclosure, an electric drive system includes: a three-phase inverter unit, a motor, a speed detection unit and a gate driver; the speed detection unit is connected to the motor and the gate driver respectively, and the speed detection unit is used to determine whether the speed state of the motor is a high-speed state or a low-speed state, and transmit the speed state to the gate driver; the gate driver is connected to the motor through a three-phase inverter unit, and the gate driver is used to control the opening or closing of a power switch tube in the three-phase inverter unit based on the speed state, so as to adjust the safety state of the electric drive system to an active short-circuit state or a winding open-circuit state, so as to detect the motor speed by adding a speed detection unit, determine the speed state of the motor, and control the opening or closing of the power switch tube in the three-phase inverter unit by the gate driver, so as to realize the control of the safety state of active short circuit or winding open circuit in the electric drive system, avoid the problem that the motor speed cannot be detected when the main control chip of the electric drive system fails, and improve the overall safety.

[0017] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present application, nor is it intended to limit the scope of the present application. Other features of the present application will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure.

[0019] Figure 1 A schematic diagram of an electric drive system provided in an embodiment of the present disclosure;

[0020] Figure 2 A schematic diagram of a specific electric drive system provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0021] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0022] An electric drive system and a means of transportation according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0023] With the development of automobile electrification and intelligence, the requirements for automobile safety are becoming higher and higher. More and more international mainstream car manufacturers are forcing their suppliers to carry out functional safety development of automotive electronic control systems in accordance with the ISO 26262 "Functional Safety of Road Vehicles" standard.

[0024] For this reason, the electric drive system of the car is proposed to prevent unexpected acceleration or deceleration. To achieve this functional safety goal, the electric drive system needs to enter different safety states according to the bus voltage, vehicle speed and other conditions. The two commonly used safety states are active short circuit (ASC) and winding open circuit (FreeWheel). When the electric drive system fails, in conventional control, the winding open circuit (FreeWheel) state is entered at a low speed to prevent the permanent magnet synchronous motor from generating unexpected braking torque. When the vehicle speed is high, the active short circuit (ASC) state is entered to prevent the permanent magnet synchronous motor from generating high passive rectification current due to high back electromotive force, thereby generating lower unexpected braking torque.

[0025] Therefore, the electric drive system also needs to detect the motor speed when a fault occurs, so as to determine the vehicle speed at the time of the fault and enter different safety states.

[0026] At present, the electric drive system of the related technology is equipped with a rotor position sensor, and the single-chip microcomputer detects the motor speed by reading the signal of the position sensor, so as to determine the safety state of the electric drive system. However, when the single-chip microcomputer fails, the motor speed cannot be detected, and the vehicle speed at the time of the failure cannot be accurately determined, and it is impossible to switch to the corresponding safety state according to the vehicle speed, which affects the overall safety of the vehicle.

[0027] In order to meet this market demand, the present disclosure proposes an electric drive system. The solution aims to add a speed detection unit to collect the voltage waveform of the back electromotive force of the motor phase line, and realize redundant detection of the motor speed by detecting the frequency of the back electromotive force voltage. When the main control chip of the electric drive system fails, the speed detection unit controls the opening or closing of the power tube through the gate driver by judging the motor speed, and controls the conversion of the safe state of active short circuit or winding open circuit in the electric drive system.

[0028] Figure 1 Schematic diagram of an electric drive system provided in an embodiment of the present disclosure. Figure 1 As shown, the circuit includes:

[0029] A three-phase inverter unit 1, a motor 2, a speed detection unit 3 and a gate driver 4;

[0030] The speed detection unit 3 is connected to the motor 2 and the gate driver 4 respectively, and the speed detection unit 3 is used to determine whether the speed state of the motor 2 is a high speed state or a low speed state, and transmit the speed state to the gate driver 4;

[0031] The gate driver 4 is connected to the motor 2 through the three-phase inverter unit 1. The gate driver 4 is used to control the opening or closing of the power switch tube in the three-phase inverter unit 1 based on the speed state to adjust the safety state of the electric drive system to an active short-circuit state or a winding open-circuit state.

[0032] The three-phase inverter unit 1 is used to convert direct current into three-phase alternating current, and includes a plurality of power switch tubes, and every two of the plurality of power switch tubes form a switch tube bridge arm. In the three-phase inverter unit, the plurality of power switch tubes can form three switch tube bridge arms.

[0033] The motor 2 of the present disclosure may be a three-phase motor, connected to a three-phase inverter unit, and driven by receiving three-phase alternating current. The motor 2 of the present disclosure may specifically be a permanent magnet synchronous motor;

[0034] The speed detection unit 3 includes a plurality of internal circuits, and through the coordinated operation of the plurality of internal circuits, the speed state of the motor can be accurately acquired, and this information is sent to the gate driver 4, so as to achieve precise control of the safety state of the electric drive system.

[0035] The gate driver 4 is used to drive the power switch tube in the three-phase inverter unit 1, and controls the opening or closing of the power switch tube according to the received speed state of the motor.

[0036] The active short-circuit state is used to prevent the motor from having a high braking torque at high speed, causing the vehicle to lose control, and a large uncontrollable feedback current that damages the high-voltage system.

[0037] The winding open circuit state means that the three-phase lines of the motor and the busbar are disconnected, and the motor can slide freely.

[0038] like Figure 2 As shown, it is a schematic diagram of a specific electric drive system provided by the present invention.

[0039] Reference Figure 2 In the embodiment of the present disclosure, the speed detection unit 3 may specifically include: a back electromotive force shaping circuit 31 , a pulse width signal conversion circuit 32 , a low-pass filter circuit 33 and a comparator circuit 34 .

[0040] Among them, the back electromotive force shaping circuit 31 is respectively connected to the motor 2 and the pulse width signal conversion circuit 32, and is used to obtain the back electromotive force signal of the motor, convert the back electromotive force signal into a square wave signal, and transmit the square wave signal to the pulse width signal conversion circuit 32; the pulse width signal conversion circuit 32 is connected to the low-pass filter circuit 33, and is used to convert the square wave signal into a fixed pulse width signal with the same frequency as the square wave signal, and transmit the fixed pulse width signal to the low-pass filter circuit 33; the low-pass filter circuit 33 is connected to the comparator circuit 34, and is used to filter the fixed pulse width signal into a DC signal, and transmit the DC signal to the comparator circuit 34; the comparator circuit 34 is connected to the gate driver 4, and is used to determine whether the DC voltage corresponding to the DC signal is greater than or equal to the threshold voltage, and determine the speed state of the motor according to the judgment result, and send the speed state to the gate driver 4.

[0041] Specifically, the gate driver 4 in the present disclosure is a dedicated integrated circuit (IC), whose main function is to convert the control signal from the speed detection unit (such as MCU, DSP, etc.) into a drive signal suitable for the fast switching of the power switch tube (such as MOSFET, IGBT, etc.). This conversion enables the power switch tube to be turned on and off quickly and reliably, thereby controlling the flow of current.

[0042] The active short-circuit state is achieved by forming a closed loop between the motor stator winding and the power switch tube (such as IGBT). In this state, the back electromotive force energy generated by the motor is released through the stator winding, and a small braking torque is generated at the output end of the motor, that is, when the speed of the motor is high and the motor speed state is high-speed, the present disclosure can adjust the safety state of the electric drive system to an active short-circuit state. When the electric drive system needs to enter the active short-circuit state, the speed detection unit sends a speed state signal of the motor to the gate driver. Based on the speed state signal of the motor, the gate driver converts the speed state signal into a high-level or low-level signal suitable for turning on or off the power switch tube.

[0043] In an optional embodiment of the present disclosure, the present disclosure can form a closed loop and realize active short-circuit protection by turning off the three power switch tubes of the upper bridge arm (i.e., the first power switch tube, the third power switch tube, and the fifth power switch tube) in the three-phase inverter unit and turning on the three power switch tubes of the lower bridge arm (i.e., the second power switch tube, the fourth power switch tube, and the sixth power switch tube), or turning on the three power switch tubes of the upper bridge arm and turning off the three power switch tubes of the lower bridge arm.

[0044] The winding open circuit state is achieved by disconnecting the connection between the power switch tube and the motor stator winding. In this state, the back electromotive force generated by the motor cannot form a closed loop and does not generate a braking torque, that is, when the speed of the motor is low and the motor speed state is in a low-speed state, the present disclosure can adjust the safe state of the electric drive collapse to the winding open circuit state. When the electric drive system needs to enter the winding open circuit state, the speed detection unit sends a speed state signal of the motor to the gate driver. Based on the speed state signal of the motor, the gate driver converts the speed state signal into a low-level signal suitable for shutting down the power switch tube.

[0045] In an optional embodiment of the present disclosure, the present disclosure can realize open circuit protection by turning on all power switch tubes of the upper bridge arm and the lower bridge arm in the three-phase inverter unit.

[0046] Among them, in the actual application of the electric drive system, the present disclosure can select appropriate gate driver types (such as low-side drivers, high-side drivers, or drivers for half-bridge and full-bridge configurations) and parameters (such as drive current, drive voltage, etc.) according to the specific requirements of the electric drive system and the characteristics of the power switch tube.

[0047] In the present disclosure, the back-EMF signal shaping circuit of the motor can obtain the back-EMF signal of the motor, convert the back-EMF signal of the motor into a square wave signal of the same frequency, thereby obtaining the frequency of the back-EMF of the motor. The relationship between the frequency f of the back-EMF and the speed n of the permanent magnet synchronous motor is n=f*120 / p (p is the number of motor poles).

[0048] The pulse width signal conversion circuit (such as the monostable trigger 74121) can output a fixed pulse width signal (i.e., a PWM signal) with the same frequency as the square wave signal by receiving the square wave signal of the back-electromotive force signal shaping circuit. The pulse width tw=k*R4C1 (K is the time coefficient of the monostable trigger). The monostable trigger current can convert the square wave signal output by the back-electromotive force signal shaping circuit into a PWM signal with a frequency of f and a duty cycle of D=tw / f.

[0049] The low-pass filter circuit is a two-pole RC low-pass filter circuit. The low-pass filter current can filter the PWM signal output by the pulse width signal conversion circuit into a DC signal, and the DC voltage is V=D*VCC.

[0050] The comparator circuit is used to determine whether the DC voltage output by the low-pass filter circuit exceeds the threshold voltage Vref, that is, by comparing the DC voltage with the threshold voltage, it is determined whether the speed (rotation speed) of the motor exceeds the set speed threshold, and the speed state of the motor is output to the gate driver. The gate driver is used to control the opening or closing of the power switch tube in the three-phase inverter unit, so as to realize different safety state control when the main control chip of the electric drive system fails.

[0051] It is understandable that the speed of the permanent magnet synchronous motor is proportional to the frequency of the back electromotive force. The higher the speed, the higher the frequency of the back electromotive force; the lower the speed, the lower the frequency of the back electromotive force. Therefore, the present disclosure can detect the motor speed by monitoring the frequency of the back electromotive force.

[0052] The present disclosure may set that when the motor speed exceeds n=120*kR4C1VCC / (p*Vref), the motor speed state signal jump may be triggered.

[0053] In some embodiments, the three-phase inverter unit 1 in the present disclosure is composed of six power switch tubes (such as IGBT, MOSFET, etc.), namely, the first power switch tube 11, the second power switch tube 12, the third power switch tube 13, the fourth power switch tube 14, the fifth power switch tube 15, and the sixth power switch tube 16. Through these six power switch tubes, three switch tube bridge arms can be formed, and each bridge arm includes two power switch tubes. By controlling the on and off states of the power switch tubes, three-phase alternating current can be generated to drive the motor.

[0054] The three-phase inverter unit includes: a first switch tube bridge arm, a second switch tube bridge arm and a third switch tube bridge arm; the first switch tube bridge arm is formed by connecting the first power switch tube 11 and the second power switch tube 12 in sequence; the second switch tube bridge arm is formed by connecting the third power switch tube 13 and the fourth power switch tube 14 in sequence; the third switch tube bridge arm is formed by connecting the fifth power switch tube 15 and the sixth power switch tube 16 in sequence.

[0055] In some embodiments, the motor 2 may include multiple inductors; the midpoint of the bridge arm of each switch tube bridge arm in the three-phase inverter unit (i.e., the connection point between each two power switch tubes in the vertical direction) is respectively connected to the multiple inductors of the motor 2 to form a three-phase drive circuit.

[0056] Specifically, the motor 2 includes three inductors. The three inductors represent the three main windings of the motor, namely the first winding 21, the second winding 22 and the third winding 23, which correspond to the three phases (U phase, V phase and W phase) of the motor respectively. These windings are arranged in a specific way inside the motor to generate a rotating magnetic field, thereby driving the motor to rotate.

[0057] In the present disclosure, the bridge arm midpoint 17 of the first switch tube bridge arm is connected to the first winding 21 (i.e., the U-phase winding) to form a first-phase drive circuit; the bridge arm midpoint 18 of the second switch tube bridge arm is connected to the second winding 22 (i.e., the V-phase winding) to form a second-phase drive circuit; the bridge arm midpoint 19 of the third switch tube bridge arm is connected to the third winding 23 (i.e., the W-phase winding) to form a third-phase drive circuit. In this way, when the gate driver 4 controls the power switch tube in the three-phase inverter unit 1 to turn on or off, corresponding currents will be generated in the three inductors of the motor 2, thereby driving the motor 2 to rotate.

[0058] In some embodiments, the back electromotive force shaping circuit 31 includes a first comparator, a first resistor R1, a second resistor R2 and a third resistor R3; the first end of the first resistor R1 is connected to the second phase drive circuit, and the second end of the third resistor R3 is connected to the third phase drive circuit; the second end of the first resistor R1 is connected to the in-phase input terminal of the first comparator; the first end of the third resistor R3 is connected to the inverting input terminal of the first comparator; the first end of the second resistor R2 is connected to the second end of the first resistor R1, and the second end of the second resistor R2 is connected to the first end of the third resistor R3; the first power supply terminal of the first comparator is connected to the power supply, and the second power supply terminal is grounded; the output terminal of the first comparator is connected to the pulse width signal conversion circuit 32.

[0059] In some embodiments, the pulse width signal conversion circuit 32 includes a monostable trigger (i.e., the monostable trigger 74121), a first capacitor C1, and a fourth resistor R4; the rising edge trigger input terminal (B) of the monostable trigger is connected to the output terminal of the first comparator; the falling edge trigger input terminal (A1, A2) of the monostable trigger is grounded; the first external capacitor terminal (Cext) of the monostable trigger is connected to the second end of the first capacitor C1; the first end of the first capacitor C1 is connected to the second external capacitor terminal (Rext / Cext) of the monostable trigger, the second external capacitor terminal is connected to the second end of the fourth resistor R4, and the first end of the fourth resistor R4 is connected to the power supply VCC; the power supply terminal of the monostable trigger is connected to the power supply VCC, and the ground terminal is grounded; the output terminal (Q) of the monostable trigger is connected to the low-pass filter circuit 33.

[0060] In some embodiments, the low-pass filter circuit 33 includes a fifth resistor R5, a sixth resistor R6, a second capacitor C2, and a third capacitor C3; the first end of the fifth resistor R5 is connected to the output end (Q) of the monostable trigger; the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6; the first end of the second capacitor C2 is connected to the second end of the fifth resistor R5, and the second end of the second capacitor C2 is grounded; the first end of the third capacitor C3 is connected to the second end of the sixth resistor R6, and the second end of the third capacitor C3 is connected to the second end of the second capacitor C2; the second end of the sixth resistor R6 is connected to the comparator circuit 34.

[0061] In some embodiments, the comparator circuit 34 includes a second comparator; the inverting input terminal of the second comparator is connected to the second end of the sixth resistor R6; the non-inverting input terminal of the second comparator is connected to the threshold voltage output terminal Vref; and the output terminal of the second comparator is connected to the gate driver 4.

[0062] The speed detection unit disclosed in the present invention uses the connection relationship of the above-mentioned internal circuits to convert the back electromotive force signal (Vuv) of the motor into a square wave signal (V1) of the same frequency using a back electromotive force signal shaping circuit, and then uses a pulse width signal conversion circuit to convert the square wave signal (V1) into a fixed pulse width signal (V2) of the same frequency, and then uses a low-pass filter circuit to filter the fixed pulse width signal (V2) into a DC signal (V3), and finally uses a comparator circuit to determine whether the DC voltage corresponding to the DC signal (V3) is greater than or equal to the threshold voltage, and determines the speed state (V4) of the motor based on the judgment result, and sends the speed state (V4) to the gate driver 4.

[0063] Among them, it should be noted that the back electromotive force shaping circuit, pulse width signal conversion circuit, low-pass filter circuit and comparator circuit in the speed detection unit of the present invention are not limited to the structures shown in the present invention. In actual usage scenarios, as long as the circuit is applicable to the electric drive system and can realize the above functions, it can also be replaced, which is not limited in the embodiments of the present invention.

[0064] In summary, through the electric drive system disclosed in the present invention, a speed detection unit is added to detect the motor speed, determine the speed state of the motor, and control the opening or closing of the power switch tube in the three-phase inverter unit through the gate driver, so as to realize the control of the safe state of active short circuit or winding open circuit in the electric drive system, avoid the problem of being unable to detect the motor speed when the main control chip of the electric drive system fails, and improve the overall safety.

[0065] According to an embodiment of the present disclosure, the present disclosure provides a means of transportation, the aforementioned charging and discharging method can be applied to the means of transportation, and the aforementioned electric drive system can be configured in the means of transportation.

[0066] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely disclosed examples consistent with some aspects of the present disclosure as detailed in the appended claims.

[0067] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0068] Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present disclosure. A person skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present disclosure.

Claims

1. An electric drive system, characterized in that: The system comprises: Three-phase inverter unit, motor, speed detection unit and gate driver; The speed detection unit is connected to the motor and the gate driver respectively, and the speed detection unit is used to determine whether the speed state of the motor is a high speed state or a low speed state, and transmit the speed state to the gate driver; The gate driver is connected to the motor via the three-phase inverter unit, and the gate driver is used to control the on or off of the power switch tube in the three-phase inverter unit based on the speed state, so as to adjust the safety state of the electric drive system to an active short-circuit state or a winding open-circuit state; The speed detection unit comprises: a back electromotive force shaping circuit, a pulse width signal conversion circuit, a low-pass filter circuit and a comparator circuit; The back electromotive force shaping circuit is connected to the motor and the pulse width signal conversion circuit respectively, and is used to obtain the back electromotive force signal of the motor, convert the back electromotive force signal into a square wave signal, and transmit the square wave signal to the pulse width signal conversion circuit; The pulse width signal conversion circuit is connected to the low-pass filter circuit, and is used to convert the square wave signal into a fixed pulse width signal with the same frequency as the square wave signal, and transmit the fixed pulse width signal to the low-pass filter circuit; The low-pass filter circuit is connected to the comparator circuit, and is used to filter the fixed pulse width signal into a DC signal, and transmit the DC signal to the comparator circuit; The comparator circuit is connected to the gate driver and is used to determine whether the DC voltage corresponding to the DC signal is greater than or equal to a threshold voltage, and determine the speed state of the motor according to the determination result, and send the speed state to the gate driver.

2. The system according to claim 1, characterized in that The three-phase inverter unit comprises: a first switch tube bridge arm, a second switch tube bridge arm and a third switch tube bridge arm; The first switch tube bridge arm is formed by sequentially connecting a first power switch tube and a second power switch tube; The second switch tube bridge arm is formed by sequentially connecting the third power switch tube and the fourth power switch tube; The third switch tube bridge arm is formed by sequentially connecting the fifth power switch tube and the sixth power switch tube.

3. The system according to claim 2, characterized in that The motor includes: a first winding, a second winding and a third winding.

4. The system according to claim 3, characterized in that The midpoint of the bridge arm of the first switch tube bridge arm is connected to the first winding to form a first phase drive circuit; The midpoint of the bridge arm of the second switch tube is connected to the second winding to form a second phase drive circuit; The midpoint of the bridge arm of the third switch tube bridge arm is connected to the third winding to form a third phase drive circuit.

5. The system according to claim 4, characterized in that The back electromotive force shaping circuit includes a first comparator, a first resistor, a second resistor and a third resistor; The first end of the first resistor is connected to the second phase driving circuit, and the second end of the third resistor is connected to the third phase driving circuit; The second end of the first resistor is connected to the non-inverting input end of the first comparator; The first end of the third resistor is connected to the inverting input end of the first comparator; The first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the first end of the third resistor; The first power supply terminal of the first comparator is connected to the power supply, and the second power supply terminal is grounded; The output end of the first comparator is connected to the pulse width signal conversion circuit.

6. The system according to claim 5, characterized in that The pulse width signal conversion circuit includes a monostable trigger, a first capacitor, and a fourth resistor; A rising edge trigger input terminal of the monostable trigger is connected to an output terminal of the first comparator; The falling edge trigger input terminal of the monostable trigger is grounded; The first external capacitor terminal of the monostable trigger is connected to the second terminal of the first capacitor; The first end of the first capacitor is connected to the second external capacitor end of the monostable trigger, the second external capacitor end is connected to the second end of the fourth resistor, and the first end of the fourth resistor is connected to the power supply; The power supply end of the monostable trigger is connected to the power supply, and the ground end is grounded; The output end of the monostable trigger is connected to the low-pass filter circuit.

7. The system according to claim 6, characterized in that The low-pass filter circuit includes a fifth resistor, a sixth resistor, a second capacitor, and a third capacitor; The first end of the fifth resistor is connected to the output end of the monostable trigger; The second end of the fifth resistor is connected to the first end of the sixth resistor; The first end of the second capacitor is connected to the second end of the fifth resistor, and the second end of the second capacitor is grounded; The first end of the third capacitor is connected to the second end of the sixth resistor, and the second end of the third capacitor is connected to the second end of the second capacitor; The second end of the sixth resistor is connected to the comparator circuit.

8. The system according to claim 7, characterized in that The comparator circuit includes a second comparator; The inverting input terminal of the second comparator is connected to the second end of the sixth resistor; The non-inverting input terminal of the second comparator is connected to the threshold voltage output terminal; An output terminal of the second comparator is connected to the gate driver.

9. A means of transport, characterized in that: Comprising an electric drive system as claimed in any one of claims 1 to 8.

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